Light emitting transducer

ABSTRACT

A light emitting transducer including a flexible sheet having a bottom side and a top side, the flexible sheet including a substrate that is stretchable and compressible, the substrate having a bottom substrate surface at the bottom side, and a top substrate surface facing towards the top side, the top substrate surface comprising a surface pattern of a plurality of raised and depressed micro-scale surface portions which extend in at least one direction; a light emitting diode layer above the substrate and conforming in shape to the top substrate surface, the light emitting diode layer corresponding with the surface pattern of the top substrate surface, wherein the light emitting diode layer has a bottom diode surface facing towards the bottom side, and a top diode surface facing towards the top side, a bottom electrode on the bottom diode surface, and a top electrode on the top diode surface.

RELATED APPLICATION DATA

This application is the national stage of International PatentApplication No. PCT/DK2018/050035 filed on Feb. 22, 2018, which claimspriority to and the benefit of Danish Patent Application No. PA 201770143 filed on Feb. 24, 2017. The entire disclosures of both of theabove applications are expressly incorporated by reference herein.

FIELD

The present disclosure relates to a transducer in the form of alight-emitting transducer of the type indicated in the preamble to claim1.

BACKGROUND

The expression transducer shall in connection with the presentdisclosure be understood as electricity to electromagnetic radiation,such as light.

It is well known that it is challenging to produce a light emittingdevice, which is flexible i.e. is capable of changing shape withoutintroducing defects to the light emitting device or at least withoutintroducing to severe lifetime destroying defects to the light emittingdevice.

This is true for the different kinds of light-emitting diodes (LED) i.e.OLED, PLED, inorganic LED.

OLED devices, which enable so-called 2.5D structure, do exist. TheseOLED devices may only be bent in one direction for each single surface.Thus, the OLED devices cannot be placed on all curved surfaces withoutintroducing severe life-time reducing defects to the structure.

One of the challenges with flexible organic LEDs is that bendingintroduces cracks in the thin film encapsulation layers, which allowsoxygen or moisture to get in contact with the organic layers, which isdetrimental to the organic layers.

Another challenge with flexible LEDs is that bending may introducecracks in transparent electrode, which is typically made of brittlematerial such as indium tin oxide (ITO).

The bending radii before introduction of severe defects in abovementioned examples are in the order of centimeters and this limits thearea of use.

EP3002798 describes a stretchable/foldable optoelectronic device. Thedevice comprises a flexible substrate having electronic layers on top ofthe substrate. The optoelectronic device is made stretchable bypre-straining the flexible substrate in a first dimension beforedepositing the electronic layers. The substrate is afterwards allowed torelax which causes the substrate to retract along the first dimension,thereby bending the electronic layers along the first dimension. Thiscauses the optoelectronic device to have wavy structure. Afterwards aforce can be applied along the first dimension and the wavy structuremay then be stretched out once more. The problem with this method ofmaking a stretchable optoelectronic device is that the wavy structure isformed randomly along the first dimension which causes theoptoelectronic device to have internal stresses, and a force applied tothe optoelectronic device may cause the layers to crack. The problem iseven larger if the substrate is pre-strained along a first and a seconddimension causing the wavy structure to be even more randomlydistributed causing the internal stresses to be even larger.

Thus, there is a need for a more reliable light emitting transducercapable of being stretched in at least one direction and a method ofproducing said light emitting transducer.

SUMMARY

It may be desirable for light emitting devices capable of bending tobending radii below the order of centimetre without the introduction ofsevere lifetime reducing cracks.

Furthermore, it may be desirable for LEDs or OLEDs capable of bending intwo directions at the same time, thereby gaining a true 3D structure. Toenable bending in two directions the LED/OLED film need to be stretchedand/or compressed.

In accordance with one or more embodiments, a transducer has a flexiblestructure, such that the field of application of the transducer inpractice may be considerably increased, and such that it is possible toattach the transducer to various surfaces and possibly varying shapes.

The light emitting transducer according to the embodiments describedherein is characterized in that a flexible sheet has a bottom side, atop side and a substrate which is stretchable and compressible.

The substrate has a bottom substrate surface at the bottom side and atop substrate surface with a micro-scale surface pattern of a pluralityof raised and depressed surface portions [structures] which extend in atleast one direction. Said top substrate surface faces towards the topside.

The micro-scale surface pattern on the top substrate surface is producedin accordance with a desired effect in mind, meaning that the wavesand/or corrugations are produced in accordance with calculated andspecified values for each of the parameters describing the plurality ofraised and depressed surface portions, these parameters being shape,amplitudes, periods and directions of the waves and/or corrugations.

The micro-scale surface pattern is defined by imprint tools forming thetop substrate surface.

The micro-scale surface pattern may be made by a hot embossing processforming the top substrate surface.

The micro-scale surface pattern may be made by a slot die castingprocess forming the top substrate surface.

The micro-scale surface pattern has a large effect on the mechanicalcharacteristics of the flexible light emitting transducer in respect offlexibility and robustness.

The substrate may be made of transparent films such as transparent PET(Polyethylene terephthalate) or PEN (Polyethylene naphthalate) or PUR/PU(Polyurethane) or PDMS Silicones (Polydimethylsiloxane) or polymerblends incorporating silicones.

The substrate may have a thickness between 5-500 μm, 10-300 μm or 30-100μm.

The substrate may be made of transparent or non-transparent polymers orpolymer blends depending on whether the light emitting transducer is abottom emitter or a top emitter. A bottom emitter emits light throughthe bottom side of the flexible sheet and a top emitter emits lightthrough the top side of the flexible sheet.

The substrate material must be flexible i.e. stretchable and/orcompressible as this property is paramount for the transducer beingbendable in one or more directions.

A light emitting diode layer is positioned above the substrate, thediode layer conforms in shape to the top substrate surface and has thesurface pattern of the raised and depressed surface portions whichextend in the at least one direction.

The diode layer has a bottom diode surface facing towards the bottomside and a top diode surface facing towards the top side.

In an embodiment the diode layer has an area of the top diode surfacethat is larger than the surface area occupied by the bottom substratesurface in a relaxed state.

The light emitting transducer further comprises a bottom electrode onthe bottom diode surface, a top electrode on the top diode surface.

The light emitting transducer may further have a top protection layerpositioned above the top electrode for improved protection.

At least one of the electrodes is transparent as the transducer iseither emitting light through the top side or the bottom side or bothsides.

The non-transparent electrode may have a thickness between 15-200 nm,20-50 nm.

The transparent electrode may have a thickness between 5-200 nm, 10-100nm or 20-50 nm.

The light emitting diode layer is less stretchable and less compressiblethan the substrate. The top electrode and the bottom electrode are alsoless stretchable and less compressible than the substrate. The diodelayer and the electrodes will typically break at an elongation below<1%. E.g. typically either the top electrode or the bottom electrode ismade of a brittle material such as ITO and it is well known that ITOwill fracture at even small elongation.

The light emitting transducer is stretchable and compressible in one ormore directions due to the design of the top substrate surface and thesubstrate material, because at least a few of the layers are neitherstretchable nor compressible when compared to substrate material.

The layers have a thickness in the order of nm and this enables thelayers to be bendable. The layers are deposited on the microscalepattern of a plurality of raised and depressed surface portions andtherefore the areas of the layers are larger than the bottom substratesurface.

The substrate is flexible and the above mentioned characteristics enablethe transducer to be both stretchable and compressible in one or moredirections even though a few of the layers are neither.

When the light emitting transducer is stretched the substrate isstretched, but the layers are not. The pattern of a plurality of raisedand depressed surface portions changes form, so that the amplitude ofthe plurality of repeating raised and depressed surface portions isdecreased while the period is increased in the stretching direction.

Thus, the layers are not stretched, but the bending of the layers isdecreased as the layers are made more flat.

The transducer may be stretched by 20-25% of the transducers lengthwithout introducing lifetime destroying defects.

When the light emitting transducer is compressed the substrate iscompressed, but the layers are not. The pattern of a plurality of raisedand depressed surface portions changes form, so that the amplitude ofthe plurality of repeating raised and depressed surface portions isincreased while the period is decreased in the compression direction.

Thus, the layers are not stretched; they are bent more.

The above described property makes the transducer compliant in certaindirection defined by the pattern of the repeated raised and depressedsurface portions. The compliancy makes the transducer able to withstandexternal and internal induced stresses.

The skilled person would recognize that the surface pattern determinesin which directions the light emitting transducer may be compressedand/or stretched; it is in those directions where the non-compressibleand non-stretchable layers may change their degree of bending.

Thus, it is possible to attach the light emitting transducer to asurface having a shape which varies over time, by way of example due toenvironmental factors, such as changes in temperature, changes inmoisture level, vibrations, shock, etc. Since the flexible properties ofthe light emitting transducer allows it to follow such changes in shapeof the surface having the light emitting transducer attached thereto, itis prevented that such changes causes damage to the light emittingtransducer, by way of example in the form of cracks, fractures ortension, and the lifetime of the transducer may thereby be prolonged.

Furthermore, the flexible characteristics of the transducer makes itpossible to attach the transducer to surfaces of various shapes, by wayof example curved surfaces, even double curved surfaces.

The transducer according to an aspect may be provided such that saidsurface pattern comprises waves forming troughs and crests extendingessentially in one common direction, each wave defining a height being ashortest distance between a crest and neighbouring troughs. According tothis embodiment, the surface pattern enables the layers to be bendablealong one bendable direction, while the surface pattern does not enablethe layers to be bendable along a direction being substantiallyperpendicular to the bendable direction. Thus, the waves define ananisotropic characteristic facilitating movement in a direction which isperpendicular to the common direction. According to this embodiment, thecrests and troughs resemble standing waves with essentially parallelwave fronts.

However, the waves are not necessarily sinusoidal, but could have anysuitable shape as long as crests and troughs are defined. According tothis embodiment a crest (or a trough) will define substantially linearcontour-lines, i.e. lines along a portion of the corrugation with equalheight relative to the substrate in general. This at least substantiallylinear line will be at least substantially parallel to similar contourlines formed by other crest and troughs, and the directions of the atleast substantially linear lines define the common direction. The commondirection defined in this manner has the consequence that anisotropyoccurs, and that flexibility of the transducer in a directionperpendicular to the common direction is facilitated, i.e. thetransducer is flexible in a direction perpendicular to the commondirection. As a consequence, the transducer can be attached to a curvedsurface without introducing cracks or creases in the transducer, becausethe transducer is capable of stretching and/or compressing along thedirection in which the layers may change the bending radii.

As an alternative, the surface pattern may comprise waves formingtroughs and crests extending essentially in at least two directionsalong the surface of the substrate. According to this embodiment, thelayers may change their degree of bending and thereby the transducer isstretchable, along at least two directions.

As a consequence, it is possible to attach the light emitting transducerto a true 3D structure without introducing cracks or creases in thetransducer, since the transducer is capable of stretching along the twocompliant directions. Thereby it is possible to attach the lightemitting transducer to a large variety of different kinds of surfaces,such as cars or other vehicles, clothing, sports equipment, facades ofbuildings, etc. It is even possible to attach the transducer to asurface, which changes shape over time.

According to one embodiment, the surface pattern may comprise wavesforming troughs and crests, said troughs and crests defining wave frontsextending essentially in at least two directions along the surface ofthe substrate. Thus, according to this embodiment, the surface patterncomprises crests similar to hilltops, the hilltops being arranged on thesurface in such a manner that substantially parallel lines can be drawnbetween groups of neighbouring hilltops, the parallel lines definingwave fronts. Such wave fronts are defined along at least two directionsalong the surface of the substrate, e.g. along two directions arrangedsubstantially perpendicularly to each other, or along three directionsarranged with a mutual angle of approximately 120°. Accordingly,similarly to what is described above, the transducer is in this caseflexible along at least two directions, i.e. the directions defined bythe extension of the wave fronts, and the transducer can thereby beattached to double curved surfaces as described above.

The light emitting transducer may have a radius of curvature in theorder of mm without introducing lifetime destroying defects.

In an aspect, the light emitting diode layer comprises one or moreorganic diodes. The person skilled in the art would be able to find andbuy the suitable organic materials from a company such as Lumtec.

The organic diode may have a thickness between 20-400 nm, 60-200 nm.

The organic diode may comprise of one or more organic layers.

In an aspect, the light emitting diode layer may comprise one or moreinorganic semiconductor diodes. The light emitting diode material may beGaAs or GaN or GaAl_(1-x)As_(x) or InGaN or any other semiconductormaterial capable of producing light in the visible spectrum. Thesemiconductor diode may have a thickness between 5-200 nm, 50-100 nm.

In an aspect, the one or more organic diodes are polymer diodes. Thepolymer diode may be based on PPV. The polymer diode may have athickness between 20-400 nm, 60-200 nm.

In an aspect, the diode layer may comprise one or more quantum dots.

The diode layer of quantum dots may have a thickness between 5-200 nm,50-100 nm.

In an aspect, the top electrode is transparent. In this embodiment thetransducer is a top emitter as the light will be emitted from the topside of the transducer.

The top electrode may be a transparent conductive electrode (TCO) beingof the oxidic types such as ITO or AlZO or SnZO or a transparentmetallic electrode (TME).

In an embodiment the bottom electrode is a metallic contact, which willwork as a reflector of the generated light thereby increasing the lightemitted from the top side.

In an aspect, the bottom electrode and the substrate are transparent.

In this embodiment the transducer is a bottom emitter as the light willbe emitted from the bottom side of the transducer, which is possible dueto the substrate and the bottom electrode being transparent.

The bottom electrode may be a transparent conductive electrode (TCO)being of the oxidic types such as ITO or AlZO or SnZO or a transparentmetallic electrode (TME).

In an embodiment the substrate is a transparent silicone substrate. Thedeposition of the TCO layer is done at a relatively high temperature,but it makes no harm to the silicone substrate, which will show nodegradation at processing temperatures up to 150° C. and limiteddegradation when in short time exposed to up to 250° C.

In an embodiment the top electrode is a metallic contact, which willwork as a reflector of the generated light thereby increasing the lightemitted from the bottom side.

In an aspect, the bottom electrode, the top electrode and the substrateare transparent. In this embodiment the transducer is a top and bottomemitter, while being transparent.

In an aspect, the transducer further comprises a bottom smoothing layerbetween the substrate and the bottom electrode.

The substrate has a pattern of raised and depressed micro-scale surfaceportions, which has a positive effect on the transducer. However, thetop substrate surface will have defects such as nanoscale hairs and/ornanoscale sharp edges extending from the surface due to the moulding ofthe substrate top surface. These nanoscale hairs and/or nanoscale sharpedges are unwanted as they reduce the quality of the transducer.

In an embodiment the nanoscale hairs and other surface defects areremoved by plasma treating the substrate top surface in an argonatmosphere. This will make the top substrate surface smoother and if thesubstrate is silicone-based then it will lead to the formation of a thinSiO_(x)-layer having a thickness of 5-100 nm. This SiO_(x)-layer has atriple function; it works as a smoothing layer and as an encapsulatinglayer which isolates the light emitting diode from the ambientatmosphere. This is particularly important for OLEDs as moisture andoxygen are damaging to the function. Furthermore, the SiO_(x)-layerworks as an adhesive layer, which will improve the connection betweenthe bottom electrode and the substrate. The thickness of the smoothinglayer will enable the layer to bend.

In an embodiment a TiO₂-layer is deposited on the top substrate surfaceafter the plasma treatment. The TiO₂-layer will like the SiO_(x) layerhave three positive effects. It will work as a smoothing layer and as anencapsulating layer which isolates the light emitting diode from theambient atmosphere. This is particularly important for OLEDs as moistureand oxygen are damaging to the function. Furthermore, the TiO₂-layerworks as an adhesive layer, which will improve the connection betweenthe bottom electrode and the substrate. The thickness of the smoothinglayer will enable the layer to bend.

In an aspect, the transducer further comprises a bottom encapsulatinglayer between the smoothing layer and the bottom electrode.

In another embodiment an extra encapsulation layer being either oxide ornitride or oxi-nitride would be deposited on the SiO_(x)-layer as itwill further isolate the light emitting diode from the ambientatmosphere, thereby extending the lifetime of the transducer. Thethickness of the layer is 5-100 nm. The thickness of the encapsulationlayer will enable the layer to bend.

In another embodiment the nanoscale hairs and other surface defects maybe covered by depositing a nitride thin film or an oxide thin film. Thethickness of the layer is 5-100 nm. The thickness of the encapsulationlayer will enable the layer to bend. The bending radii would be in theorder of mm.

In an aspect, the transducer further comprises a top encapsulating layerabove the top electrode. The top encapsulating layer may be a nitridethin film or an oxide thin film. The skilled person would know whichthin film to deposit based upon the wanted layers. The thickness of thelayer is 5-200 nm, 20-100 nm. The thickness of the encapsulation layerwill enable the layer to bend. The bending radii would be in the orderof mm.

In an aspect, the transducer may further comprise a bottom encapsulatinglayer below the bottom electrode and above the substrate. The bottomencapsulating layer may be a nitride thin film or an oxide thin film.The skilled person would know which thin film to deposit based upon thewanted layers. The thickness of the layer is 5-200 nm, 20-100 nm. Thiswill further increase the lifetime of the transducer, which would bebetter isolated from the ambient atmosphere. The thickness of theencapsulation layer will enable the layer to bend. The bending radiiwould be in the order of mm.

In an aspect, the top electrode comprises of a conductive polymer.

The conductive polymer may be materials such as PEDOT or PEDOT:PSS(poly(3,4-ethylenedioxythiophene) polystyrene sulfonate) or conductivesilicone blends. The conductive polymer has a conductivity which isabout a million times smaller than metal, but the thickness of thepolymer will typically be 0.2-10 μm or 0.5-5 μm or 1-2 μm.

The conductive polymer will due to the production method have a planartop electrode surface, which allows the front protection layer to beflat. This enables application where the transducer is mounted on aplanar surface of a device or a 2.5D surface of a device or a 3D surfaceof a device. This may be done by laminating the top surface of the frontprotection layer onto the surface of a device. The planar top side makesfor a robust and easy to laminate transducer. The PEDOT layer will makethe transducer less flexible compared to a transducer not having a PEDOTlayer. However, the transducer will still be able to be mounted on aplanar surface of a device or a 2.5D surface of a device or a 3D surfaceof a device as long as the curvature is not too great.

One of the benefits of conductive polymers is that they are easy tohandle as they can be cured by heating the conductive polymer to atemperature above 80° C., which is non-damaging to the transducer.

In an aspect, the top electrode may further comprise a metallicelectrode between the conductive polymer and diode layer.

The combination of a metallic electrode and a conductive polymer isdefined as a composite electrode. The composite electrode brings twoenhancements of the transducer performance. First it brings a morerobust electrode where loss of conduction related to potential cracks inthe rather brittle electrode is reduced due to the conductive polymerelectrode making short-circuits across the cracks. Secondly with thecomposite electrode it is easier to make an electrical connection to thediode.

In an aspect, the pattern is repeated with a period between 100-1000 mm.

Advantageously the pattern is created using a roll as a mask. This maskmay have a circumference of 100-1000 mm, 200-600 mm or 300-400 mm.

This will enable transducer to be produced in a roll-to-roll process,which will keep the manufacturing cost down.

In an aspect, the raised and depressed surface portions are randomlydistributed on a micrometre scale. By having a randomly formed surface,the light will escape in a diffuse way suitable for creating a subtlelighting element ideal for providing a luminescent layer and avoidingdiffractive grading effects from linear periodic patterns. The surfaceis randomly formed on the micro-scale, however repeating on the largermm/cm scale. This may be done by using a roll.

In an aspect, the pattern is orderly formed. From a given orderly formedsurface, the light will escape in an orderly predetermined manner, e.g.directing the light emittance in given directions and by that performingas a light processing surface such as providing diffractive opticaleffects, structural coloration or holographic coloration.

In some embodiments the orderly pattern may be used to detect thecompression or stretching of a structure by attaching the transducer tothe surface of the structure. If the structure changes shape thediffractive optical effects, structural coloration or holographiccoloration of the transducer will also change.

In an embodiment the bottom substrate surface is matte. The mattesurface will ensure that the emitted light from the transducer isdiffused light, and interference patterns, structural coloration,holographic colorations and iridescence is reduced or avoided.

In an embodiment the bottom substrate surface is smooth. The smoothsurface will ensure that the emitted light from the transducer is directlight, which will enable interference patterns, structural coloration,holographic colorations and iridescence.

In an aspect, the bottom substrate surface is a lens.

The lens may be a concave or convex or a Fresnel lens.

The flexibility of the transducer will allow the lens to changedimensions in a controlled way, so that the optical characteristics ischanged, e.g. enabling variable focus length or variations in thedirection of emitted light.

In an aspect, the light emitting transducer is mounted on a siliconelens.

The lens may be a concave or convex or a Fresnel lens. The lens may haveother shapes. The flexibility of the transducer will allow the lens tochange dimensions in a controlled way, so that the opticalcharacteristics is changed, e.g. enabling variable focus length orvariations in the direction of emitted light

In an aspect, the layers and the electrodes above the substrate has athickness, which is 1/50 to 1/100 of a height difference between therepeating raised and depressed micro-scale surface portions. The abovementioned proportions are important as it enables the transducer to bestretched or compressed in the compliant directions without introductionof lifetime destroying defects.

In an embodiment transducer may have two or more wave fronts and theheight difference along a line perpendicular to the wave fronts may bedifferent. This will affect the transducer as the stretchability willdecrease if the height difference decreases. Thus, transducer may bemore or less compliant in certain directions depending on the heightdifference of the repeating raised and depressed surface portions inthose directions.

In an aspect, the repeating raised and depressed micro-scale surfaceportions has a height difference of 5-50 μm.

The light emitting transducer can be mounted in various ways, whenapplied as a lighting device. The transducer may be mounted as acurtain, connected electrically and mechanically along only the one sideof a sheet of film. In this configuration the flexible stretchable filmbrings lighting device with the design expression like a curtain.

The light emitting transducer may be mounted as a sheet of film in aframe, connected mechanically along all sides to a mechanically stableframe and connected electrically along one or more sides. The frame canbe made of a stable stiff material and the LED/OLED/PLED film is in aplanar or non-planar geometry. The frame can be integrated part of atextile or similar flexible nature, and in this configuration thelighting device has the design expression of a wearable clothes with theintegrated feature of emitting light

The light emitting transducer may be mounted on a flat 2D or curved 2½ Dsolid surface. In this configuration the rear flat surface of thesubstrate is laminated to the flat 2D or curved 2½ D surface and thelighting device has the design expression of the 2D or curved 2½ Dsurface. The flexibility and stretchability of the LED/OLED/PLED filmallows for the film to adapt to the 2D or curved 2½ D during mountingand lamination of the film to the surface, however also allows for thepart (with the 2D or curved 2½ D) to change shape due to appliedforces/stresses or applied change of temperature.

The light emitting transducer may be mounted on a 3D solid surface. Inthis configuration the rear flat surface of the substrate is laminatedto the full 3D surface and the lighting device has the design expressionof the full 3D surface. The flexibility and stretchability of theLED/OLED/PLED film allows for the film to adapt to the 3D surface duringmounting and lamination of the film to the surface, however also allowsfor the part (with full 3D shapes) to change shape due to appliedforces/stresses or applied change of temperature.

In an aspect, the substrate is an optical element. The substrate as anoptical element can be used to focus and/or control the light emitted bythe light emitting transducer. The optical element may be planar,concave or convex. The optical element may have a Fresnel lensstructure.

On way of making the substrate into an optical element is by merging thesubstrate of the transducer with an optical element being of the samematerial as the substrate. The transducer and the optical element can bemerged by first heating the transducer and the optical element followedby an act of pressing the two components together. In this way thetransition from the substrate to the optical element is so good withregards to the optical characteristics (constant refractive index) thatthe substrate may be seen as a single optical element.

In an aspect, the bottom substrate surface is a lens, the lens can beused to focus and/or control the light emitted by the transducer. Thebottom substrate surface may be planar, concave or convex. The lens mayhave a Fresnel lens structure on the bottom substrate surface.

In an aspect, the transducer may be mounted on a silicone lens. Thelight emitted by the transducer can be controlled by the lens. Each sideof the lens may be planar, concave, convex or Fresnel.

When mounting the flexible transducer on a silicone lens the flexibilityof the transducer may allow the lens to change dimensions in acontrolled way, so that the optical characteristics is changeable, e.g.enabling variable focus length or variations in the direction of emittedlight.

An optical element may have a first surface and a second surface and inbetween a silicone material. A transducer is attached to one surface.

The optical element may control pathway of light moving towards and/orfrom the transducer.

The optical element may be a silicone lens, which like the transducer isflexible. When mounting the flexible transducer on a silicone lens theflexibility of the transducer may allow the lens to change dimensions ina controlled way, so that the optical characteristics is changeable,e.g. enabling variable focus length or variations in the pathway ofelectromagnetic waves.

The transducer may be a solar cell and/or a thermoelectric transducer.

The transducer may be a light-emitting transducer.

The light-emitting transducer may comprise of one or more organic diodesor one or more semiconductor diodes or one or more polymer diodes or oneor more quantum dots or a combination of the previous mentioned types.

In an aspect, the light emitting diode layer may comprise a plurality ofdiodes. This will increase the usability of the transducer as it can beused as a simple lighting device, but the plurality of diodes enablesthe transducer to be used as a display.

A suitable top substrate surface will enable the display to bendable intwo directions at the same time, thereby gaining a true 3D structure.

The display would also be foldable. In an embodiment the plurality ofdiodes are controlled by a passive matrix as the passive matrix iseasier and thereby cheaper to make.

In an embodiment the plurality of diodes are controlled by an activematrix. The active matrix gives a greater control over each diode.

In an embodiment the transducer may have three different types ofdiodes, where each type have different emission spectrums such as red,green and blue. This enables the transducer to produce different coloursand white light.

In an embodiment the different diodes of the transducer may havedifferent sizes in order to compensate for different effects such asquantum efficiency or degradation due to drive current density.

In an aspect, the light emitting transducer may further comprise aTFT-array having a plurality of interconnected thin-film transistors,each thin-film transistor being near a diode of the plurality of diodes.

The thin-film transistor (TFT) array will enable each diode to becontrolled by a control unit. The control unit may switch the diodeon/off or control the light intensity.

The TFT will behave like the other electrodes when the transducer isstretched in directions defined by the surface pattern. If the topsubstrate surface pattern enables the transducer to be stretchable andcompressible in two directions, then the transducer having a TFT-arraywould be a display capable of bending in two directions, i.e. a true 3Dstructure.

In an embodiment the TFT-array is positioned above the top electrode andconnected to the top electrode. If the light emitting transducer is abottom emitter the TFT-array will be positioned above the top electrodein order to minimise the interaction with the emitted light.

In an embodiment the TFT-array is below the bottom electrode andconnected to the bottom electrode. If the light emitting transducer is atop emitter the TFT-array will be positioned below the bottom electrodein order to minimise the interaction with the emitted light.

In an embodiment the light emitting diode layer has an isolation elementin between neighbouring diodes. The isolation element will minimisecross-talk between neighbouring diodes, which will increase the qualityof the display.

In an embodiment adjacent diodes are grouped in emission groups, whereeach emission group is capable of producing white light. The individualdiodes may have different emission spectrums such as red, green and blueor any other combination where the addition of the individual spectrumssums to white light. The subpixels of the emission group may then becontrolled by the TFT-array to produce the different colours in thevisible spectrum.

In an embodiment the plurality of diodes comprises at least one diodeemitting white light. In order to give a sufficient light intensity thedisplay may have at least one diode producing white light. The whitelight emitting diodes could be phosphor-coated LEDs or stacked organicdiodes.

In an embodiment the plurality of diodes are stacked organic diodes,which comprises two or more light emitting organic layers.

In an embodiment the stacked organic diodes produce white light, whichenables the transducer to be used as a white light source. Together withthe design of the light emitting transducer this makes it possible toplace the light emitting transducer on curved or double curved surfaces,thus the usability is greatly enhanced.

In an embodiment neighbouring stacked organic diodes are grouped incolour groups comprising at least three stacked organic diodes. Thestacked organic diodes in the colour group may be controlledindividually.

In an embodiment the transducer further comprises a colour mask beingpositioned below the bottom electrode. If the transducer is a bottomemitter the colour mask will be positioned below the bottom electrode.

The colour mask may have three different colour filters such as red,green and blue, as it will enable the colour group to produce thecolours of the visible spectrum. The colour mask could have a differentnumber of filters and different kinds.

The colour mask may have a transparent filter, which can be used toincrease the light intensity. The colour mask is aligned with thestacked organic diodes, such that each filter in the colour mask willfilter the light of a single stacked organic diode. This design willmake the production of the diode layer simpler as all the stackedorganic diodes are similar.

In an embodiment the transducer further comprises a colour mask beingpositioned above the top electrode. If the transducer is a top emitterthe colour mask will be positioned above the top electrode.

The colour mask may have three different colour filters such as red,green and blue, as it will enable the colour group to produce thecolours of the visible spectrum. The colour mask could have a differentnumber of filters and different kinds. The colour mask may have atransparent filter, which can be used to increase the light intensity.The colour mask is aligned with the stacked organic diodes, such thateach filter in the colour mask will filter the light of a single stackedorganic diode. This design will make the production of the diode layersimpler as all the stacked organic diodes are similar.

In an aspect, the thin-film transistors are organic thin-filmtransistors as it is possible to deposit the organic thin-filmtransistors at a temperature of around 150° C. The silicone substratewill degrade at higher temperatures such as 250° C., thus to avoiddegradation the TFT-array has to be deposited at low temperature.

In an aspect, the thin-film transistors are oxide thin-film transistors(Such as IGZO) as it is possible to deposit the oxide thin-filmtransistors at a temperature of around 150° C. The silicone substratewill degrade at temperatures above 150° C., thus to avoid degradationthe TFT-array has to be deposited at low temperature.

In an aspect, the thin-film transistors are nitride thin-filmtransistors, such as GaN, which can be deposited at a temperature of250° C.

A method for production of a transducer for use as a display maycomprise one or more of the following acts.

There may be an act of providing a stretchable and compressiblesubstrate having a bottom substrate surface and a top substrate surfacewith a surface pattern of a plurality of repeating raised and depressedmicro-scale surface portions which extend in at least one direction.

In an embodiment the substrate having the top substrate surface with thesurface pattern of a plurality of repeating raised and depressedmicro-scale surface portions is made in a slot die coating process.

In an embodiment the substrate having the top substrate surface with thesurface pattern of a plurality of repeating raised and depressedmicro-scale surface portions is made in a hot embossing process.

The micro-structured surface portions may have a period in the range of5-10 μm and an amplitude of up to the period i.e. up to 5-10 μm.

In another embodiment the micro-structured surface portions may have aperiod in the range of 2-5 μm and an amplitude of up to the period i.e.up to 2-5 μm.

There may be an act of adhering the bottom substrate surface to agas-permeable carrier for prevention of substrate movements.

The acts of depositing several layers at several stations on astretchable polymer substrate rely heavily on the ability to get thecorrect alignment of the mask and substrate.

Thus, it is important that all surface portions of the substrate are inthe same relaxed state and at same position on the carrier at all times.

When working with a flexible substrate the substrate may also changeshape due to forces related to changes in temperature.

The flexible substrate is secured by adhering the planar bottomsubstrate surface to the top course of the carrier. This may be done bymaking the surface of the carrier sticky or by making the planar bottomsubstrate surface sticky.

The carrier is gas-permeable, which allows small pockets of otherwisetrapped gas between the carrier and the substrate to escape the pocketswhen subjecting the substrate to vacuum conditions.

In an embodiment the carrier is a perforate steel plate. The perforatesteel plate will allow the gas to escape through the bottom of theholes. The surface of the steel plate may be coated with a stickymaterial, which enables the substrate to be adhered to the surface ofthe steel plate.

If the substrate moves or parts of the substrate move the alignmentbetween the plurality of masks and the structures on the substratechanges, this misalignment will cause the transducer or parts of thetransducer to be non-working.

The alignment of the mask with the substrate is in particular critical,when depositing the oxide diode or the oxide-TFT layer due to thesmaller size of the structures and the surface pattern on the topsubstrate surface.

Thus, the adhering enables the production of an OLED transducer capableof functioning as a flexible display.

In another embodiment the carrier may be cooled. This will increase thecooling of the substrate, which should not be subjected to temperaturesabove 250° C. and should only for brief periods of time be subjected totemperatures above 150° C. Some of the acts of depositing will be attemperatures above the 250° C. limit, but the cooling will keep thesubstrate below the 250° C. limit. Thus, the quality of the lightemitting transducer is increased by the cooling as the substrate willsuffer degradation to a lesser extent.

If the substrate is not cooled through the carrier, each act ofdepositing material will be divided into smaller steps of depositingfollowed by a time step, where the substrate will cool passively. Thus,the carrier cooling will also decrease the production time.

In an embodiment the carrier is cooled to a temperature of 20-30° C.

There may be an act of plasma treating the top substrate surface. Theplasma treatment may be in an argon/oxygen atmosphere. The plasmatreatment will make the micro-scale surface portions smoother as theremay be unwanted surface elements, such as nano-scale hairs andnano-scale edges, which will lower the quality of the light emittingtransducer if not removed.

In an embodiment the substrate is silicone or silicone-based and if thissubstrate is plasma treated then the top substrate surface will form athin SiO_(x) layer, which may further function as an encapsulation layerisolating the organic material from the ambient atmosphere containingoxygen and moisture.

There will be repeated acts of placing shadow masks above the topsubstrate surface, wherein each shadow mask has a design suitable for aspecific deposition step. The openings will have edge to edge distances,which are shorter compared to the desired structures of the depositedmaterial.

The surface pattern complicates the deposition of material; because thesurface pattern prohibits the shadow mask from making a perfect clamp onthe uppermost surface. The depressed surface portions will leaveopenings in between the shadow mask and the uppermost surface. This willcause shadow effects, wherein material will be deposited outside theopenings defined by the shadow mask. Thus, the shadow effects willperturb the deposition of material when using a shadow mask havingunder-dimensioned openings, such that the deposited material has thedesired structure.

Studies have shown that the period of the raised and depressed surfaceportions have an impact on the maximum extend of the shadow effects.

Assuming one nominal dimension of a pixel of the active layer to be0.085 mm (corresponding approximately 300 pixels/inch) and assuming theperiod of the depressed and raised surface portions is approximately0.005 mm, then the distance edge to edge of the opening in the maskshould be reduced by approximately 0.0025 mm (½ period) to 0.0825 mm.Depending on the deposition process used the tolerances on the dimensionedge to edge of the pixel should be expected to increase by a maximum0.0025 mm.

Furthermore, the size of these shadow effects is in the same order ofmagnitude as the tolerance on the edge to edge distance of the openings.

There will be repeated acts of removing said shadow mask afterdeposition.

There may be an act of depositing a transparent bottom electrode on thetop substrate surface.

The bottom electrode may be deposited by PVD techniques in an argonatmosphere.

The bottom electrode may be deposited by bipolar MF sputtering in anargon atmosphere.

The bottom electrode may be deposited by RF sputtering in an argonatmosphere.

The bottom electrode may be deposited by CVD or PECVD in an argonatmosphere.

The transparent bottom electrode will cover most of the top substratesurface in order to get a good contact with the next oxide layer.

In an embodiment the transparent electrode is an ITO electrode. The workfunction of ITO is almost as large as HOMO of the organic material, thusthe ITO is particular suitable for injection of holes into the organiclayer; i.e. it may function as an anode.

There may be an act of depositing a colour group of organic pixels onthe bottom electrode comprising one or more steps of depositing organiclayers on top of each other. The organic pixels in a colour group willhave similar emission spectrums.

A classic RGB-display will therefore have three colour groups; however adisplay may have any number of colour groups.

Furthermore, the size of the pixels of the different colour groups mayhave different sizes as the organic material used in the differentcolour groups may have different properties regarding emissionefficiency and current density degradation.

In an embodiment the organic layers are deposited using vacuum thermalevaporation technique.

In an embodiment a hole injection layer may be deposited onto the ITO asit will help the injection of holes from the ITO layer to the organiclayer. This may be followed by an act of deposition of a hole transportlayer for transportations of holes. This may be followed by an emittinglayer, where electrons and holes will recombine while emitting light.

In an embodiment the organic pixels may further comprise an electrontransport layer on the emitting layer.

There may be an act of depositing a TFT-layer comprising one or moresteps of depositing conductive electrodes, insulation layers, thin-filmtransistors.

The thin-film transistors may be oxide or organic as they can bedeposited at temperatures, which will not degrade the substrate or willonly degrade the substrate slightly. The deposition of the TFT-layer maybe done by a combined set of PVD, CVD and PECVD processes.

The conductive electrodes deposited will be the data and gate lines.Depending on the surface pattern the electrodes may have to be depositedin certain direction.

In an embodiment the substrate may have a surface pattern having aplurality of wave fronts in one common direction; similar to FIG. 11. Inthis embodiment the conductive electrodes must be deposited in adirection perpendicular to the wave fronts as they would otherwise breakat a short elongation when the transducer is stretched.

In an embodiment the substrate may have a surface pattern having asuperposition of at least two wave fronts; similar to FIG. 12. In thisembodiment the conductive electrodes can be deposited in an arbitrarydirection relative to the wave fronts as the electrodes will not breakwhen the transducer is stretched and/or compressed.

The oxide thin-film transistor may be of IGZO type. IGZO may be depositat a temperature of 150° C., which the substrate may be subjected for atime without severe degradation.

In an embodiment the isolation layers are made of silicon oxide (SiO₂),aluminium oxide (Al₂O₃), SiO₂ doped with boron or phosphorous or organiclayers such as parylene (pply(p-xylylene)).

There may be an act of depositing a top electrode on the organic pixels.The metallic top electrode may be deposited by PVD-techniques.

The PVD-technique could be DC-sputtering.

The PVD-technique could be pulsed DC sputtering.

The PVD-technique could be bipolar MF.

The PVD-technique could be high power impulse magnetron sputtering.

In an embodiment the top electrode comprises of a single Al layer.Aluminium has a work function similar to the HOMO level of the organiclayer and this makes aluminium a good electron injector.

The top electrode may comprise of a LiF layer in contact with theorganic layer for better injection of electrons into the organic layer.On top of the LiF there may be Al layer.

There may be an act of depositing a protective non-conductive layer. Theprotective non-conductive layer may be deposited by use of bipolar MFsputtering process in an atmosphere being a mix of argon, oxygen andnitrogen.

The method for producing a transducer may further comprise an act ofdepositing one or more encapsulation layers above said TFT-layer.

The encapsulation layer may be deposited by use of a bipolar MFsputtering process in an atmosphere of argon, oxygen and nitrogen.

The encapsulation layer is impermeable for oxygen and moisture andtherefore it will increase the lifetime of the transducer. Theencapsulation layer may be oxide based. The encapsulation layer may benitride based. The encapsulation layer may be oxi-nitride based.

The method for producing a transducer may further comprise an act ofdepositing an encapsulation layer on the top substrate surface. Theencapsulation layer may be deposited by use of a bipolar MF sputteringprocess in an atmosphere of argon, oxygen and nitrogen.

The substrate may be permeable for oxygen and/or moisture, thus oxygenand/or moisture will over time diffuse through the substrate towards theorganic layers and this would damage the OLED. Thus, the encapsulationlayer which is impermeable for oxygen and moisture will increase thelifetime of the transducer. The encapsulation layer may be oxide based.The encapsulation layer may be nitride based. The encapsulation layermay be oxi-nitride based.

There may be more than one encapsulation layers on the top substratesurface.

A method for producing a transducer for light illumination may compriseone or more of the following acts.

In an embodiment the substrate having the top substrate surface with thesurface pattern of a plurality of repeating raised and depressedmicro-scale surface portions is made in a slot die casting process.

In an embodiment the substrate having the top substrate surface with thesurface pattern of a plurality of repeating raised and depressedmicro-scale surface portions is made in a hot embossing process.

The micro-structured surface portions may have a period in the range of5-10 μm and an amplitude of up to the period i.e. up to 5-10 μm.

In another embodiment the micro-structured surface portions may have aperiod in the range of 2-5 μm and an amplitude of up to the period i.e.up to 2-5 μm.

There may be an act of adhering the bottom substrate surface to agas-permeable carrier for prevention of substrate movements.

The acts of depositing several layers at several stations on astretchable polymer substrate rely heavily on the ability to get thecorrect alignment of the mask and substrate.

Thus, it is important that all surface portions of the substrate are inthe same relaxed state and at same position on the carrier at all times.When working with a flexible substrate the substrate may also changeshape due to forces related to changes in temperature.

The flexible substrate is secured by adhering the planar bottomsubstrate surface to the top course of the carrier. This may be done bymaking the surface of the carrier sticky or by making the planar bottomsubstrate surface sticky.

The carrier is gas-permeable, which allows small pockets of otherwisetrapped gas between the carrier and the substrate to escape the pocketswhen subjecting the substrate to vacuum conditions.

In an embodiment the carrier is a perforate steel plate. The perforatesteel plate will allow the gas to escape through the bottom of theholes. The surface of the steel plate may be coated with a stickymaterial, which enables the substrate to be adhered to the surface ofthe steel plate.

If the substrate moves or parts of the substrate move the alignmentbetween the plurality of masks and the structures on the substratechanges, this misalignment will cause the transducer or parts of thetransducer to be non-working. Thus, the adhering enables the productionof an OLED transducer capable of functioning as a flexible lightemitting device.

In another embodiment the carrier may be cooled. This will increase thecooling of the substrate, which should not be subjected to temperaturesabove 250° C. and should only for brief periods of time be subjected totemperatures above 150° C. Some of the acts of depositing will be attemperatures above the 250° C. limit, but the cooling will keep thesubstrate below the 250° C. limit. Thus, the quality of the transduceris increased by the cooling as the substrate will suffer degradation toa lesser extent.

If the substrate is not cooled through the carrier, each act ofdepositing material will be divided into smaller steps of depositingfollowed by a time step, where the substrate will cool passively. Thus,the carrier cooling will also decrease the production time.

In an embodiment the carrier is cooled to a temperature of 20-30° C.

There may be an act of plasma treating the top substrate surface. Theplasma treatment may be in an argon/oxygen atmosphere. The plasmatreatment will make the micro-scale surface portions smoother as theremay be unwanted surface elements, such as nano-scale hairs andnano-scale edges, which will lower the quality of the transducer if notremoved.

In an embodiment the substrate is silicone or silicone-based and if thissubstrate is plasma treated then the top substrate surface will form athin SiO_(x) layer, which may further function as an encapsulation layerisolating the organic material from the ambient atmosphere containingoxygen and moisture.

There will be repeated acts of placing shadow masks above the topsubstrate surface, wherein each shadow mask has a design suitable aspecific deposition step. Each deposition will have a particular shadowmask with suitable openings. The openings will have edge to edgedistances, which are shorter compared to the desired structures of thedeposited material.

The surface pattern complicates the deposition of material; because thesurface pattern prohibits the shadow mask from making a perfect clamp onthe uppermost surface. The depressed surface portions will leaveopenings in between the shadow mask and the uppermost surface. This willcause shadow effects, wherein material will be deposited outside theopenings defined by the shadow mask. Thus, the shadow effects willperturb the deposition of material when using a shadow mask havingunder-dimensioned openings, such that the deposited material has thedesired structure.

Studies have shown that the period of the raised and depressed surfaceportions have an impact on the maximum extend of the shadow effects.

Assuming one nominal dimension of a pixel of the active layer to be0.085 mm (corresponding approximately 300 pixels/inch) and assuming theperiod of the depressed and raised surface portions is approximately0.005 mm, then the distance edge to edge of the opening in the maskshould be reduced by approximately 0.0025 mm (½ period) to 0.0825 mm.Depending on the deposition process used the tolerances on the dimensionedge to edge of the pixel should be expected to increase by a maximum0.0025 mm.

Furthermore, the size of these shadow effects is in the same order ofmagnitude as the tolerance on the edge to edge distance of the openings.

There will be repeated acts of removing said shadow mask afterdeposition.

There may be an act of depositing a transparent bottom electrode on thetop substrate surface. The bottom electrode may be deposited by PVDtechniques in an argon atmosphere. The bottom electrode may be depositedby bipolar MF sputtering in an argon atmosphere. The bottom electrodemay be deposited by RF sputtering in an argon atmosphere. The bottomelectrode may be deposited by CVD or PECVD in an argon atmosphere.

The transparent bottom electrode will cover most of the top substratesurface in order to get a good contact with the next oxide layer.

In an embodiment the transparent electrode is an ITO electrode. The workfunction of ITO is almost as large as the HOMO level of the organicmaterial, thus the ITO is particular suitable for injection of holesinto the organic layer; i.e. it may function as an anode.

There may an act of depositing an organic layer on top of the bottomelectrode, the organic layer may comprise of several organic sublayers.

In an embodiment the organic layer comprises red, green and blue organicdiodes placed side by side. Each organic diode will comprise of one ormore organic sublayers, which may increase the quality of the organicdiodes.

In an embodiment a hole injection layer may be deposited onto the ITO asit will help the injection of holes from the ITO layer to the organiclayer. This may be followed by an act of deposition of a hole transportlayer for transportations of holes. This may be followed by an emittinglayer, where electrons and holes will recombine while emitting light.

In an embodiment the organic layer comprises a plurality of stackedorganic diodes. The stacked organic diodes will have a better luminancevalue compared to a non-stacked architecture.

There may be an act of depositing a top electrode on the organic pixels.The metallic top electrode may be deposited by PVD-techniques. ThePVD-technique could be DC-sputtering. The PVD-technique could be pulsedDC sputtering. The PVD-technique could be bipolar MF. The PVD-techniquecould be high power impulse magnetron sputtering.

In an embodiment the top electrode comprises of a single Al layer.Aluminium has a work function similar to the HOMO level of the organiclayer and this makes aluminium a good electron injector.

The top electrode may comprise of a LiF layer in contact with theorganic layer for better injection of electrons into the organic layer.On top of the LiF there may be Al layer.

Method for producing a transducer for light illumination may furthercomprise one or more of the following acts;

There may be an act of depositing a protective non-conductive layer. Theprotective non-conductive layer may be deposited by use of bipolar MFsputtering process in an atmosphere being a mix of argon, oxygen andnitrogen.

The method for producing a transducer may further comprise an act ofdepositing an encapsulation layer above said top electrode.

The encapsulation layer may be deposited by use of a bipolar MFsputtering process in an atmosphere of argon, oxygen and nitrogen.

The protective non-conductive layer may be permeable for oxygen and/ormoisture, thus oxygen and/or moisture will over time diffuse through thenon-conductive layer towards the organic layers and this would damagethe OLED. Thus, the encapsulation layer which is impermeable for oxygenand moisture will increase the lifetime of the transducer.

The encapsulation layer may be oxide based.

The encapsulation layer may be nitride based.

The encapsulation layer may be oxi-nitride based.

There may be more than one encapsulation layers above the top electrode,thereby creating a laminated structure having an even lower oxygen andmoisture diffusion rate.

The method for producing a transducer may further comprise an act ofdepositing an encapsulation layer on the top substrate surface. Theencapsulation layer may be deposited by use of a bipolar MF sputteringprocess in an atmosphere of argon, oxygen and nitrogen.

The substrate may be permeable for oxygen and/or moisture, thus oxygenand/or moisture will over time diffuse through the substrate towards theorganic layers and this would damage the OLED. Thus, the encapsulationlayer which is impermeable for oxygen and moisture will increase thelifetime of the transducer. The encapsulation layer may be oxide based.The encapsulation layer may be nitride based. The encapsulation layermay be oxi-nitride based.

There may be more than one encapsulation layers on the top substratesurface, thereby creating a laminated structure having an even loweroxygen and moisture diffusion rate.

The transducer according to one or more embodiments described herein ischaracterized in that said substrate is constituted by a flexible,elastic web or foil, that a front side of said substrate has athree-dimensional surface pattern of raised and depressed surfaceportions formed therein, said light emitting diode layer being depositedonto said three-dimensional surface pattern, that said front sideelectrode and rear side electrode are constituted by electric conductivelayers, which comprise electric conductive materials, or which isprovided with an electric conductive coatings.

A light emitting transducer includes: a flexible sheet having a bottomside and a top side, the flexible sheet including: a substrate that isstretchable and compressible, the substrate having a bottom substratesurface at the bottom side, and a top substrate surface facing towardsthe top side, the top substrate surface comprising a surface pattern ofa plurality of raised and depressed micro-scale surface portions whichextend in at least one direction; a light emitting diode layer above thesubstrate and conforming in shape to the top substrate surface, thelight emitting diode layer corresponding with the surface pattern of thetop substrate surface, wherein the light emitting diode layer has abottom diode surface facing towards the bottom side, and a top diodesurface facing towards the top side, a bottom electrode on the bottomdiode surface; and a top electrode on the top diode surface.

Optionally, the light emitting diode layer comprises a plurality ofdiodes.

Optionally, the light emitting diode layer comprises one or more organicdiodes.

Optionally, the light emitting diode layer comprises one or moreinorganic semiconductor diodes.

Optionally, the one or more organic diodes are one or more polymerdiodes.

Optionally, the light emitting diode layer comprises one or more quantumdots.

Optionally, the bottom electrode and the substrate are transparent.

Optionally, the top electrode is transparent.

Optionally, the light emitting transducer further includes a bottomsmoothing layer between the substrate and the bottom electrode.

Optionally, the bottom smoothing layer comprises SiO_(x).

Optionally, the light emitting transducer further includes a bottomencapsulating layer below the bottom electrode and above the substrate.

Optionally, the light emitting transducer further includes a topencapsulating layer above the top electrode.

Optionally, the bottom encapsulating layer comprises a nitride basedlayer or an oxide based layer or oxi-nitride based.

Optionally, the top encapsulating layer comprises a nitride based layeror an oxide based layer or oxi-nitride based.

Optionally, the top electrode comprises a conductive polymer.

Optionally, the top electrode has a planar top electrode surface.

Optionally, the top electrode further comprises a metallic electrodebetween the conductive polymer and the light emitting diode layer.

Optionally, the surface pattern is repeated with a period between100-1000 mm.

Optionally, the raised and depressed micro-scale surface portions arerandomly distributed on a micrometre scale.

Optionally, the surface pattern is orderly formed.

Optionally, all components of the light emitting transducer above thesubstrate form a thickness, which is 1/50 to 1/100 of a heightdifference between the repeating raised and depressed micro-scalesurface portions.

Optionally, the raised and depressed micro-scale surface portions have aheight difference of 5-50 μm.

Optionally, the light emitting transducer further includes a TFT-arrayhaving a plurality of interconnected thin-film transistors, thethin-film transistor corresponding with respective diodes at the lightemitting diode layer.

Optionally, the thin-film transistors comprise organic thin-filmtransistors.

Optionally, the thin-film transistors comprise oxide thin-filmtransistors.

Optionally, the thin-film transistors comprise nitride thin filmtransistors.

Optionally, the thin-film transistors comprise oxi-nitride thin filmtransistors.

Optionally, the substrate is an optical element.

Optionally, the bottom substrate surface is a lens.

Optionally, the light emitting transducer is mounted on a silicone lens.

An optical element includes a first surface, a second surface, and asilicone material between the first surface and the second surface,wherein the optical element further comprises the transducer attached tothe first surface or the second surface.

Optionally, the light emitting transducer further includes a protectionlayer above the top electrode, the protection layer comprising anelastic web or foil. Optionally, the light emitting diode layer is lessstretchable and less compressible than the substrate.

A method for producing a light emitting transducer for lightillumination includes: providing a stretchable and compressiblesubstrate having a bottom substrate surface and a top substrate surfacewith a surface pattern of a plurality of raised and depressedmicro-scale surface portions which extend in at least one direction;adhering the bottom substrate surface of the substrate to agas-permeable carrier for prevention of movement of the substrate;plasma treating the top substrate surface of the substrate; placing oneor more shadow masks above the top substrate surface, wherein each ofthe one or more shadow masks has a design suitable for a specificdeposition; removing the one or more shadow masks; depositing atransparent bottom electrode on the top substrate surface; depositing anorganic layer; and depositing a top electrode on the organic layer.

Optionally, the method further includes one or a combination of:depositing an encapsulation layer above the top electrode, depositing anencapsulation layer on the top substrate surface of the substrate,depositing a protective non-conductive layer.

A method for producing a light emitting transducer for a displayincludes: providing a stretchable and compressible substrate having abottom substrate surface and a top substrate surface with a surfacepattern of a plurality of raised and depressed micro-scale surfaceportions which extend in at least one direction; adhering the bottomsubstrate surface of the substrate to a gas-permeable carrier forprevention of movement of the substrate; plasma treating the topsubstrate surface of the substrate; placing one or more shadow masksabove the top substrate surface, wherein each of the shadow masks has adesign suitable for a specific deposition; removing the one or moreshadow masks; depositing a transparent bottom electrode on the topsubstrate surface; depositing a colour group of organic pixels on thebottom electrode, wherein the act of depositing the colour group oforganic pixels comprises depositing organic layers; depositing a topelectrode on the organic pixels; and depositing an TFT-layer, whereinthe act of depositing the TFT-layer comprises depositing conductiveelectrodes, insulation layers, and thin film transistors.

Optionally, the method further includes one or a combination of:depositing an encapsulation layer above the TFT-layer, depositing anencapsulation layer on the top substrate surface of the substrate,depositing a protective non-conductive layer.

A light emitting transducer produced by the method described herein.

Other features and advantageous will be described in the detaileddescription.

DESCRIPTION OF THE DRAWING

The embodiments are described in more detail with reference to thedrawing, in which:

FIG. 1 illustrates a top emitter architecture;

FIG. 2 illustrates a bottom emitter architecture;

FIG. 3 illustrates a bottom emitter architecture including a smoothinglayer;

FIG. 4 illustrates a bottom emitter architecture including a SiOxsmoothing layer;

FIG. 5 illustrates a bottom emitter architecture including one or moreencapsulating layers;

FIG. 6 illustrates a bottom emitter architecture having a planar topsurface;

FIG. 7 illustrates a bottom emitter architecture having a planar topsurface and a composite top electrode;

FIG. 8 illustrates a top and bottom emitter architecture;

FIG. 9 illustrates a flexible film mounted on a silicone lens;

FIG. 10 illustrates a transducer mounted on a silicone lens;

FIG. 11 illustrates the compliancy of the transducer;

FIG. 12 illustrates two different embodiments of the top substratesurface;

FIG. 13 illustrates an embodiment of a light emitting transducer for adisplay; and

FIG. 14 illustrates a SEM photo of a top substrate surface havingparallel wave fronts.

DETAILED DESCRIPTION

Various embodiments are described hereinafter with reference to thefigures. It should be noted that the figures may or may not be drawn toscale and that elements of similar structures or functions arerepresented by like reference numerals throughout the figures. It shouldalso be noted that the figures are only intended to facilitate thedescription of the embodiments. They are not intended as an exhaustivedescription of the claimed invention or as a limitation on the scope ofthe claimed invention. In addition, an illustrated embodiment needs nothave all the aspects or advantages of the invention shown. An aspect oran advantage described in conjunction with a particular embodiment isnot necessarily limited to that embodiment and can be practiced in anyother embodiments even if not so illustrated or if not so explicitlydescribed.

FIG. 1 illustrates a top emitter architecture, which comprises asubstrate having a bottom substrate surface and a top substrate surface.The top substrate surface has a pattern of repeated raised and depressedsurface portions, which extends in at least one direction.

The substrate may be made of transparent or non-transparent polymer orpolymer blends.

The substrate may have a design like but not limited to the disclosedsurfaces in FIG. 11 or 12.

The top emitter architecture further comprises a bottom electrodepositioned on the top substrate surface and conforming in shape to topsubstrate surface.

The bottom electrode is a metallic electrode or a transparent conductiveelectrode (TCO).

A diode layer is positioned to the bottom electrode and conforms inshape to the top substrate surface. Thereby the diode layer has thepattern of repeated raised and depressed surface portions.

The diode layer has a bottom diode layer surface facing towards thebottom side and a top diode layer surface facing towards the top sideand with an area of the top diode surface layer that is larger than thesurface area occupied by the bottom substrate surface in relaxed state.

The diode layer may comprise one or more organic diodes or one or moreinorganic semiconductor diodes or one or more polymer diodes or one ormore quantum dots.

A transparent top electrode of the TCO or TME type is positioned on thetop diode layer surface and conforming in shape to the pattern of raisedand depressed surface portions.

A transparent top protection layer is positioned on the top of thetransparent top electrode and conforms in shape to the pattern of raisedand depressed surface portions.

The transparent top protection layer will work as a protectionprolonging the lifetime of the light emitting diode.

The top emitter architecture will emit light in a general directionindicated by the arrow 11.

FIG. 2 illustrates bottom emitter architecture, which comprises atransparent substrate having a bottom substrate surface and a topsubstrate surface. The top substrate surface has a pattern of repeatedraised and depressed surface portions, which extends in at least onedirection.

The substrate may be made of transparent PET or PEN or PUR/PU or PDMSsilicones or polymer blends incorporating silicones.

The substrate may have a design like but not limited to the disclosedsurfaces in FIG. 11 or 12.

The top emitter architecture further comprises a transparent bottomelectrode positioned on the top substrate surface and conforming inshape to top substrate surface.

The transparent bottom electrode is of the TCO or TME type.

A diode layer is positioned to the bottom electrode and conforms inshape to the top substrate surface. Thereby the diode layer has thepattern of repeated raised and depressed surface portions.

The diode layer has a bottom diode layer surface facing towards thebottom side and a top diode layer surface facing towards the top sideand with an area of the top diode surface layer that is larger than thesurface area occupied by the bottom substrate surface in relaxed state.

The diode layer may comprise one or more organic diodes or one or moreinorganic semiconductor diodes or one or more polymer diodes or one ormore quantum dots.

A top electrode is positioned on the top diode layer surface andconforming in shape to the pattern of raised and depressed surfaceportions.

The top electrode is a metallic electrode or a transparent conductiveelectrode (TCO).

A top protection layer is positioned on the top of the top electrode andconforms in shape to the pattern of repeated raised and depressedsurface portions.

The top protection layer will work as a protection prolonging thelifetime of the light emitting diode.

The bottom emitter architecture will emit light in a general directionindicated by the arrow 11.

FIG. 3 illustrates a bottom emitter architecture including a smoothinglayer. The bottom emitter architecture comprises a transparent substratehaving a bottom substrate surface and a top substrate surface. The topsubstrate surface has a pattern of raised and depressed surfaceportions, which extends in at least one direction.

The substrate may be made of transparent PET or PEN or PUR/PU or PDMSsilicones or polymer blends incorporating silicones.

The substrate may have a design like but not limited to the disclosedsurfaces in FIG. 11 or 12.

A smoothing layer is on the top substrate surface. The smoothing layermay be formed by plasma treatment in an argon atmosphere; thereby thetop substrate surface is reconstructed. This may also transform ofresidual compounds on the top substrate surface.

If the substrate is based on PDMS Silicones (Polydimethylsiloxane) orPolymer blends incorporating silicones then the surface treatment willform microscopic quartz crystals SiO_(x) on the top substrate surface.

The smoothing surface will have less micro/nano-edges compared to thetop substrate surface and the minimum radii will also be greater.

Thus, the smoothing surface will improve the quality of the transducer.

The bottom emitter architecture further comprises a transparent bottomelectrode positioned on the smoothing layer and conforming in shape totop substrate surface.

The transparent bottom electrode is of the TCO or TME type.

A diode layer is positioned to the bottom electrode and conforms inshape to the top substrate surface. Thereby the diode layer has thepattern of repeated raised and depressed surface portions.

The diode layer has a bottom diode layer surface facing towards thebottom side and a top diode layer surface facing towards the top sideand with an area of the top diode surface layer that is larger than thesurface area occupied by the bottom substrate surface in relaxed state.

The diode layer may comprise one or more organic diodes or one or moreinorganic semiconductor diodes or one or more polymer diodes or one ormore quantum dots.

A top electrode is positioned on the top diode layer surface andconforming in shape to the pattern of repeated raised and depressedsurface portions.

The top electrode is a metallic electrode or a transparent conductiveelectrode (TCO).

A top protection layer is positioned on the top of the top electrode andconforms in shape to the pattern of repeated raised and depressedsurface portions.

The top protection layer will work as a protection prolonging thelifetime of the light emitting diode.

The bottom emitter architecture will emit light in a general directionindicated by the arrow 11.

FIG. 4 illustrates a bottom emitter architecture including a SiO_(x)smoothing layer. The bottom emitter architecture comprises a transparentsubstrate having a bottom substrate surface and a top substrate surface.The top substrate surface has a pattern of repeated raised and depressedsurface portions, which extends in at least one direction.

The substrate may be made of transparent PDMS silicones or polymerblends incorporating silicones.

The substrate may have a design like but not limited to the disclosedsurfaces in FIG. 11 or 12.

A smoothing layer is on the top substrate surface. The smoothing layeris formed by depositing SiO_(x) on the top substrate surface.

The smoothing surface will have less micro/nano-edges compared to thetop substrate surface and the minimum radii will also be greater.

This will improve the quality of the transducer and the adherence issignificantly improved for the subsequent application of further layer.

The bottom emitter architecture further comprises a transparent bottomelectrode positioned on the smoothing layer and conforming in shape totop substrate surface.

The transparent bottom electrode is of the TCO or TME type.

A diode layer is positioned to the bottom electrode and conforms inshape to the top substrate surface. Thereby the diode layer has thepattern of raised and depressed surface portions.

The diode layer has a bottom diode layer surface facing towards thebottom side and a top diode layer surface facing towards the top sideand with an area of the top diode surface layer that is larger than thesurface area occupied by the bottom substrate surface in relaxed state.

The diode layer may comprise one or more organic diodes or one or moreinorganic semiconductor diodes or one or more polymer diodes or one ormore quantum dots.

A top electrode is positioned on the top diode layer surface andconforming in shape to the pattern of repeated raised and depressedsurface portions.

The top electrode is a metallic electrode or a transparent conductiveelectrode (TCO).

A top protection layer is positioned on the top of the top electrode andconforms in shape to the pattern of repeated raised and depressedsurface portions.

The top protection layer will work as a protection prolonging thelifetime of the light emitting diode.

The bottom emitter architecture will emit light in a general directionindicated by the arrow 11.

FIG. 5 illustrates a bottom emitter architecture including one or moreencapsulating layers. The bottom emitter architecture comprises atransparent substrate having a bottom substrate surface and a topsubstrate surface. The top substrate surface has a pattern of repeatedraised and depressed surface portions, which extends in at least onedirection.

The substrate may be made of transparent PET or PEN or PUR/PU or PDMSsilicones or polymer blends incorporating silicones.

The substrate may have a design like but not limited to the disclosedsurfaces in FIG. 11 or 12.

One or more encapsulating layers are above the top substrate surface.The encapsulating layers may be formed by depositing SiO_(x) or otherquarts grain structures on the top substrate surface. This may befollowed by one or more layers of either oxide or nitride or oxi-nitridecompounds.

The combined effect of the one or more encapsulating layers is that theorganic layer is protected by from the ambient atmosphere, in particularwater and oxygen.

The smoothing surface will have less micro/nano-edges compared to thetop substrate surface and the minimum radii will also be greater.

The bottom emitter architecture further comprises a transparent bottomelectrode positioned on the smoothing layer and conforming in shape totop substrate surface.

The transparent bottom electrode is of the TCO or TME type.

A diode layer is positioned to the bottom electrode and conforms inshape to the top substrate surface. Thereby the diode layer has thepattern of repeated raised and depressed surface portions.

The diode layer has a bottom diode layer surface facing towards thebottom side and a top diode layer surface facing towards the top sideand with an area of the top diode surface layer that is larger than thesurface area occupied by the bottom substrate surface in relaxed state.

The diode layer may comprise one or more organic diodes or one or moreinorganic semiconductor diodes or one or more polymer diodes or one ormore quantum dots.

A top electrode is positioned on the top diode layer surface andconforming in shape to the pattern of raised and depressed surfaceportions.

The top electrode is a metallic electrode or a transparent conductiveelectrode (TCO).

A top protection layer is positioned on the top of the top electrode andconforms in shape to the pattern of raised and depressed surfaceportions.

The top protection layer will work as a protection prolonging thelifetime of the light emitting diode.

The bottom emitter architecture will emit light in a general directionindicated by the arrow 11.

FIG. 6 illustrates a bottom emitter architecture having a planar topsurface. The bottom emitter architecture comprises a transparentsubstrate having a bottom substrate surface and a top substrate surface.The top substrate surface has a pattern of repeated raised and depressedsurface portions, which extends in at least one direction.

The substrate may be made of transparent PET or PEN or PUR/PU or PDMSsilicones or polymer blends incorporating silicones.

The substrate may have a design like but not limited to the disclosedsurfaces in FIG. 11 or 12.

A smoothing layer is on the top substrate surface. The smoothing layermay be formed by plasma treatment in an argon atmosphere; thereby thetop substrate surface is reconstructed. This may also transform ofresidual compounds on the top substrate surface.

The smoothing layer may be formed by depositing SiO_(x) on the topsubstrate surface.

The smoothing layer may comprise of a combination of the top substratesurface being plasma treated in an argon atmosphere, and if thesubstrate is not made of PDMS silicones or polymer blends incorporatingsilicones then the plasma treatment is followed by an act of depositingSiO_(x).

The smoothing surface will have less micro/nano-edges compared to thetop substrate surface and the minimum radii will also be greater.

The bottom emitter architecture further comprises a transparent bottomelectrode positioned on the smoothing layer and conforming in shape totop substrate surface.

The transparent bottom electrode is of the TCO or TME type.

A diode layer is positioned to the bottom electrode and conforms inshape to the top substrate surface. Thereby the diode layer has thepattern of raised and depressed surface portions.

The diode layer has a bottom diode layer surface facing towards thebottom side and a top diode layer surface facing towards the top sideand with an area of the top diode surface layer that is larger than thesurface area occupied by the bottom substrate surface in relaxed state.

The diode layer may comprise one or more organic diodes or one or moreinorganic semiconductor diodes or one or more polymer diodes or one ormore quantum dots.

A conductive polymer top electrode is positioned on the top diode layersurface and conforming in shape to the pattern of raised and depressedsurface portions.

The conductive polymer top electrode is made of a conductive polymersuch as PEDOT or PEDOT:PSS or a conductive silicone blend.

The conductive polymer top electrode has a planar top electrode surface.

A top protection layer is positioned on the planar top electrodesurface.

The top protection layer will work as encapsulation layer prolonging thelifetime of the light emitting diode by protecting the organic layerfrom the ambient atmosphere.

The bottom emitter architecture will emit light in a general directionindicated by the arrow 11.

FIG. 7 illustrates a bottom emitter architecture having a planar topsurface and a composite top electrode.

The bottom emitter architecture comprises a transparent substrate havinga bottom substrate surface and a top substrate surface. The topsubstrate surface has a pattern of repeated raised and depressed surfaceportions, which extends in at least one direction.

The substrate may be made of transparent PET or PEN or PUR/PU or PDMSsilicones or polymer blends incorporating silicones.

The substrate may have a design like but not limited to the disclosedsurfaces in FIG. 11 or 12.

A smoothing layer is on the top substrate surface. The smoothing layermay be formed by plasma treatment in an argon atmosphere; thereby thetop substrate surface is reconstructed. This may also transform ofresidual compounds on the top substrate surface.

The smoothing layer may be formed by depositing SiO_(x) on the topsubstrate surface.

The smoothing layer may comprise of a combination of the top substratesurface being plasma treated in an argon atmosphere, followed by an actof depositing SiO_(x).

The smoothing surface will have less micro/nano-edges compared to thetop substrate surface and the minimum radii will also be greater.

The bottom emitter architecture further comprises a transparent bottomelectrode positioned on the smoothing layer and conforming in shape totop substrate surface.

The transparent bottom electrode is of the TCO or TME type.

A diode layer is positioned to the bottom electrode and conforms inshape to the top substrate surface. Thereby the diode layer has thepattern of repeated raised and depressed surface portions.

The diode layer has a bottom diode layer surface facing towards thebottom side and a top diode layer surface facing towards the top sideand with an area of the top organic surface layer that is larger thanthe surface area occupied by the bottom substrate surface in relaxedstate.

The diode layer may comprise one or more organic diodes or one or moreinorganic semiconductor diodes or one or more polymer diodes or one ormore quantum dots.

A conductive polymer top electrode is positioned on the top organiclayer surface and conforming in shape to the pattern of repeated raisedand depressed surface portions.

The conductive polymer top electrode is made of a conductive polymersuch as PEDOT or PEDOT:PSS or a conductive silicone blend.

The conductive polymer top electrode has a planar top electrode surface

A top protection layer is positioned on the planar top electrodesurface.

The top protection layer will work as encapsulation layer prolonging thelifetime of the by protecting the organic layer from the ambientatmosphere.

The bottom emitter OLED architecture will emit light in a generaldirection indicated by the arrow 11.

FIG. 8 illustrates a top and bottom emitter architecture. The top andbottom emitter architecture comprises a transparent substrate having abottom substrate surface and a top substrate surface. The top substratesurface has a pattern of raised and depressed surface portions, whichextends in at least one direction.

The substrate may be made of transparent PET or PEN or PUR/PU or PDMSsilicones or polymer blends incorporating silicones.

The substrate may have a design like but not limited to the disclosedsurfaces in FIG. 11 or 12.

A smoothing layer is on the top substrate surface. The smoothing layermay be formed by plasma treatment in an argon atmosphere; thereby thetop substrate surface is reconstructed. This may also transform ofresidual compounds on the top substrate surface.

If the substrate is based on PDMS Silicones (Polydimethylsiloxane) orPolymer blends incorporating silicones then the surface treatment willform microscopic quartz crystals SiO_(x) on the top substrate surface.

The smoothing surface will have less micro/nano-edges compared to thetop substrate surface and the minimum radii will also be greater.

Thus, the smoothing surface will improve the quality of the transducer.

The bottom and top emitter architecture further comprises a transparentbottom electrode positioned on the smoothing layer and conforming inshape to top substrate surface.

The transparent bottom electrode is of the TCO or TME type.

A diode layer is positioned to the bottom electrode and conforms inshape to the top substrate surface. Thereby the diode layer has thepattern of repeated raised and depressed surface portions.

The diode layer has a bottom diode layer surface facing towards thebottom side and a top diode layer surface facing towards the top sideand with an area of the top diode surface layer that is larger than thesurface area occupied by the bottom substrate surface in relaxed state.

The diode layer may comprise one or more organic diodes or one or moreinorganic semiconductor diodes or one or more polymer diodes or one ormore quantum dots.

A transparent top electrode is positioned on the top diode layer surfaceand conforming in shape to the pattern of repeated raised and depressedsurface portions.

The transparent top electrode is of the TCO or TME type. A topprotection layer is positioned on the top of the top electrode andconforms in shape to the pattern of repeated raised and depressedsurface portions.

The top protection layer will work as a protection prolonging thelifetime of the light emitting diode.

The top and bottom emitter architecture will emit light in a directionsindicated by the arrows 11, 11′.

FIG. 9 illustrates a bottom emitter architecture having a lens shapedbottom surface. The transducer may have a layer structure similar toFIG. 1-8 and a top substrate surface similar but not limited to thesurfaces disclosed in FIG. 11 or 12.

The transducer has a lens shaped bottom surface. The lens shape can beconcave as in FIG. 9 or convex. The lens may also be a Fresnel lens.

FIGS. 9A and 9B shows a bottom emitter architecture having a lens shapedbottom surface having concave lenses with different curvatures.

FIG. 10 illustrates a transducer mounted on an optical element.

The transducer may have a layer structure similar to FIG. 1-8 and a topsubstrate surface similar but not limited to the surfaces disclosed inFIG. 11 or 12.

The transducer is mounted on a silicone lens. The silicone lens shapecan be concave as in FIG. 10 or convex. The optical element may also bea Fresnel lens

FIGS. 10A and 10B shows a transducer mounted on silicone lenses havingconcave lenses with different curvatures. The optical element may be asilicone lens.

FIG. 11 illustrates the compliancy of the transducer. The transducer inFIG. 11A-B has a series of wave fronts in a direction. The substrate ofthe transducer is flexible as it can be stretch and compressed in alldirections, but this is not the case for the transducer in FIG. 11A-B asit can only stretch and/or compress in a single direction.

The layers on the top substrate surface are neither stretchable norcompressible and the layers will break at elongation <1%. However, thelayers are thin and this makes them bendable. If a force is applied tothe transducer in a direction perpendicular to the wave fronts thetransducer will stretch or compress in that direction. FIG. 11Billustrates what happens if the transducer is stretched to a length ofL′. The substrate stretches, but the layers do not stretch. The bendingof the layers is decreased as the transducer stretches and the surfacepattern of the plurality of repeating raised and depressed micro-scalesurface portions is changed as the wavelength is increased and theamplitude is decreased.

If a force is applied to the transducer in a direction parallel to thewave fronts the layers will crack.

Thus, the transducer in FIG. 11A-B is compliant in a directionperpendicular to the wave fronts.

FIG. 12 illustrates two different embodiments of the top substratesurface. Each substrate is compliant in two directions, which areperpendicular to each other. This enables the transducer to be stretchedand/or compressed in two directions at the same time, i.e. thetransducer may conform to a true 3D surface.

FIG. 13 illustrates an embodiment of a light emitting transducer for adisplay.

FIG. 13A discloses a close-up of a single diode comprising a substrate1, a bottom encapsulation layer 6 for reducing the diffusion of moistureand oxygen towards the light emitting diode layer 3, a bottom electrode2, a light emitting diode 13 a, a top electrode 4 on the light emittingdiode layer 3 a connected to a thin-film transistor for of the lightemission of the single diode and a top encapsulation layer 6′ forreducing the diffusion of moisture and oxygen towards the light emittingdiode layer 3.

The light emitting diode 13 a may be an organic diode emitting red,green, blue or any other colour.

FIG. 13A discloses an RGB-group comprising three light emitting diodes13 a, 13 b and 13 c. Thereby the transducer may produce any colour.

As described above, the silicone substrate in itself possesses elasticproperties allowing the substrate to be stretched to some extent.However, providing the surface of the silicone substrate with a surfacepattern defining troughs and crests along one, two or more directionssignificantly enhances the elastic properties of the substrate. Itshould be noted that the elasticity of the transducer renders thetransducer robust with respect to changes in the dimensions and/or shapeof a surface having the transducer attached thereto, since theelasticity of the transducer allows it to change its shape to follow thechanges in the mounting surface. This prolongs the expected lifetime ofthe transducer and allows it to be attached to an even larger variety ofdifferent kinds of surfaces. Changes in the dimensions and/or shape of asurface having the transducer attached thereto may by way of example becaused by environmental influences, such as changes in temperature,changes in moisture level, vibrations, shocks, etc.

Production of a transducer according to the form of an OLED lightingdevice on a substrate in the form of a preferably silicone web, foil orsheet, may be characterized in carrying said silicone web, foil or sheetwith said front side facing upwards supported on a top course of acarrier, being an endless conveyor or a similar transportation unit insuccessive order through the following treatment stations, where atreatment station can include a cluster of treatment equipment:

-   -   in a first treatment station providing said surface pattern of        the front side of said substrate 1 with a plasma treating in an        argon/oxygen (Ar/O₂) atmosphere,    -   in a second treatment station applying a rear side transparent        conductive electrode 2 onto the plasma treated surface, a shadow        mask is placed on top of the substrate, the layer is deposited        by bipolar MF sputtering in an argon (Ar) atmosphere, and shadow        mask is removed    -   in a third treatment station applying one or more group of        layers each consisting of a light emitting layer, a hole        transport layer and a hole injection layer on to said surface        pattern of the front side of said electrode, the layers are        deposited in a repeating sequence of placing shadow masks is on        top of the substrate, depositing layer by Vacuum Thermal        Evaporation technique, and removing shadow masks    -   in a fourth treatment station applying a front side electrode 4,        being an electric conductive layer, the layer is deposited by        placing a shadow mask, depositing the layer by DC or pulsed DC        sputtering in an argon (Ar) atmosphere, and removing the shadow        mask    -   in a fifth treatment station applying a protective        non-conductive layer by use of a bipolar MF sputtering process        in an atmosphere being a mix of argon (Ar), oxygen (O2) and        Nitrogen (N)    -   in a potential final treatment station, a rotating winding        station is winding up the finished web, foil of substrate        including OLEDs, alternative the finished sheet of substrate        including OLEDs is stacked.

Extra treatment stations applying encapsulation layers can optional beinserted in above described series of treatments, e.g.

-   -   in an extra treatment station after first treatment station and        before second treatment station applying an encapsulation layer        by use of a bipolar MF sputtering process in an atmosphere being        a mix of argon (Ar), oxygen (O2) and Nitrogen (N)    -   in an extra treatment station after fourth treatment station and        before fifth treatment station applying an encapsulation layer        by use of a bipolar MF sputtering process in an atmosphere being        a mix of argon (Ar), oxygen (O2) and Nitrogen (N)

Production of a transducer according to the form of an OLED displaydevice on a substrate in the form of a preferably silicone web, foil orsheet, may be characterized in carrying said silicone web, foil or sheetwith said front side facing upwards supported on a top course of acarrier, being an endless conveyor or a similar transportation unit insuccessive order through the following treatment stations, where atreatment station can include a cluster of treatment equipment:

-   -   in a first treatment station providing said surface pattern of        the front side of said substrate 1 with a plasma treating in an        argon/oxygen (Ar/O₂) atmosphere,    -   in a second treatment station applying a rear side transparent        conductive electrode 2 onto the plasma treated surface, a shadow        mask is placed on top of the substrate, the layer is deposited        by bipolar MF sputtering in an argon (Ar) atmosphere, and shadow        mask is removed    -   in a third treatment station applying the pixels in one or more        group of layers each consisting of a light emitting layer, a        hole transport layer and a hole injection layer on to said        surface pattern of the front side of said electrode is deposited        in a repeating sequence of placing shadow masks is on top of the        substrate, depositing layer by Vacuum Thermal Evaporation        technique, and removing shadow masks    -   in a forth treatment station applying the switching matrix        backplane consisting of one or more group of layers of        conducting electrodes, insulation layers and the Oxide TFT (Thin        Film Transistor) layer on to said surface pattern of the front        side of said electrode is deposited in a repeating sequence of        placing shadow masks is on top of the substrate, depositing        layers by a combined set of PVD, CVD and PECVD processes and        removing shadow mask;    -   in a fifth treatment station applying an protective        non-conductive layer by use of a bipolar MF sputtering process        in an atmosphere being a mix of argon (Ar), oxygen (O2) and        Nitrogen (N); and    -   in a potential final treatment station, a rotating winding        station is winding up the finished web, foil of substrate        including OLEDs, alternative the finished sheet of substrate        including OLEDs is stacked.

Extra treatment stations applying encapsulation layers can optional beinserted in above described series of treatments, e.g.

-   -   in an extra treatment station after first treatment station and        before second treatment station applying an encapsulation layer        by use of a bipolar MF sputtering process in an atmosphere being        a mix of argon (Ar), oxygen (O2) and Nitrogen (N)    -   in an extra treatment station after forth treatment station and        before fifth treatment station applying an encapsulation layer        by use of a bipolar MF sputtering process in an atmosphere being        a mix of argon (Ar), oxygen (O2) and Nitrogen (N)

FIG. 14 illustrates an SEM photo of a top substrate surface havingparallel wave fronts, see dotted lines. The top substrate surface isorderly formed and can be made in a slot die casting process or a hotembossing process. Each wave front is parallel to all the other wavefronts.

The substrate is stretchable in the direction parallel to the wavefronts.

DRAWING REFERENCE NUMBERS

-   -   1: Substrate    -   2: Bottom electrode    -   3: Light emitting diode layer    -   4: Top electrode    -   6: Smoothing/encapsulation layer    -   9: Transducer    -   10: Top protective layer (possibly transparent)    -   11: Emitted light    -   12: Thin-film transistor    -   13: Diode    -   20: Bottom side    -   21: Top side

1. A method for producing a light emitting transducer for lightillumination comprising: providing a stretchable and compressiblesubstrate having a bottom substrate surface and a top substrate surface,the substrate surface having a surface pattern of a plurality of raisedand depressed micro-scale surface portions which extend in at least onedirection; adhering the bottom substrate surface of the substrate to agas-permeable carrier for prevention of movement of the substrate;plasma treating the top substrate surface of the substrate; placing oneor more shadow masks above the top substrate surface, wherein each ofthe one or more shadow masks has a design suitable for a specificdeposition; removing the one or more shadow masks; depositing atransparent bottom electrode on the top substrate surface; depositing anorganic layer; and depositing a top electrode on the organic layer. 2.The method according to claim 1, wherein the plurality of raised anddepressed micro-scale surface portions extend in two directions.
 3. Thelight emitting transducer according to claim 1 or 2, wherein the surfacepattern is formed by imprint tools.
 4. The light emitting transduceraccording to claim 1 or 2, wherein the surface pattern is formed by ahot embossing process.
 5. The light emitting transducer according toclaim 1 or 2, wherein the surface pattern is formed by a slot diecasting process.
 6. The method according to one or more of claims 1-5,further comprising one or a combination of: depositing an encapsulationlayer above the top electrode, depositing an encapsulation layer on thetop substrate surface of the substrate, depositing a protectivenon-conductive layer.
 7. A method for producing a light emittingtransducer for a display comprising: providing a stretchable andcompressible substrate having a bottom substrate surface and a topsubstrate surface, the substrate surface having a surface pattern of aplurality of raised and depressed micro-scale surface portions whichextend in at least one direction; adhering the bottom substrate surfaceof the substrate to a gas-permeable carrier for prevention of movementof the substrate; plasma treating the top substrate surface of thesubstrate; placing one or more shadow masks above the top substratesurface, wherein each of the shadow masks has a design suitable for aspecific deposition; removing the one or more shadow masks; depositing atransparent bottom electrode on the top substrate surface; depositing acolour group of organic pixels on the bottom electrode, wherein the actof depositing the colour group of organic pixels comprises depositingorganic layers; depositing a top electrode on the organic pixels; anddepositing an TFT-layer, wherein the act of depositing the TFT-layercomprises depositing conductive electrodes, insulation layers, and thinfilm transistors.
 8. The method according to claim 7, wherein theplurality of raised and depressed micro-scale surface portions extend intwo directions.
 9. The light emitting transducer according to claim 7 or8, wherein the surface pattern is formed by imprint tools.
 10. The lightemitting transducer according to claim 7 or 8, wherein the surfacepattern is formed by a hot embossing process.
 11. The light emittingtransducer according to claim 7 or 8, wherein the surface pattern isformed by a slot die casting process.
 12. The method according to one ormore of claim 7-11, further comprising one or a combination of:depositing an encapsulation layer above the TFT-layer, depositing anencapsulation layer on the top substrate surface of the substrate,depositing a protective non-conductive layer.
 13. A light emittingtransducer produced by the method of any of claims 1-12.
 14. A lightemitting transducer comprising: a flexible sheet having a bottom sideand a top side, the flexible sheet including: a substrate that isstretchable and compressible, the substrate having a bottom substratesurface at the bottom side, and a top substrate surface facing towardsthe top side, the top substrate surface comprising a surface pattern ofa plurality of raised and depressed micro-scale surface portions whichextend in at least one direction; a light emitting diode layer above thesubstrate and conforming in shape to the top substrate surface, thelight emitting diode layer corresponding with the surface pattern of thetop substrate surface, wherein the light emitting diode layer has abottom diode surface facing towards the bottom side, and a top diodesurface facing towards the top side, a bottom electrode on the bottomdiode surface; and a top electrode on the top diode surface.
 15. Thelight emitting transducer according to claim 14, wherein the pluralityof raised and depressed micro-scale surface portions extend in twodirections.
 16. The light emitting transducer according to claim 14 or15, wherein the surface pattern is formed by imprint tools.
 17. Thelight emitting transducer according to claim 14 or 15, wherein thesurface pattern is formed by a hot embossing process.
 18. The lightemitting transducer according to claim 14 or 15, wherein the surfacepattern is formed by a slot die casting process.
 19. The light emittingtransducer according to any one of claims 14-18, wherein the pluralityof raised and depressed micro-scale surface portions define parallelwave fronts in one or two directions.
 20. The light emitting transduceraccording to any of claims 14-19, wherein the surface pattern isrepeated with a period between 100-1000 mm.
 21. The light emittingtransducer according to any of claims 14-20, wherein the raised anddepressed micro-scale surface portions are randomly distributed on amicrometre scale.
 22. The light emitting transducer according to any ofclaims 14-21, wherein the surface pattern is orderly formed.
 23. Thelight emitting transducer according to any of claims 14-22, wherein thelight emitting diode layer comprises a plurality of diodes.
 24. Thelight emitting transducer according to any of claims 15-22, wherein thelight emitting diode layer comprises one or more organic diodes.
 25. Thelight emitting transducer according any of claims 15-22, wherein thelight emitting diode layer comprises one or more inorganic semiconductordiodes.
 26. The light emitting transducer according to claim 24, whereinthe one or more organic diodes are one or more polymer diodes.
 27. Thelight emitting transducer according to any of claims 14-22, wherein thelight emitting diode layer comprises one or more quantum dots.
 28. Thelight emitting transducer according to any of claims 14-27, wherein thebottom electrode and the substrate are transparent.
 29. The lightemitting transducer according to any of claims 14-28, wherein the topelectrode is transparent.
 30. The light emitting transducer according toany of claims 14-29, further comprising a bottom smoothing layer betweenthe substrate and the bottom electrode.
 31. The light emittingtransducer according to claim 30, wherein the bottom smoothing layercomprises SiO_(x).
 32. The light emitting transducer according to any ofclaims 14-31, further comprising a bottom encapsulating layer below thebottom electrode and above the substrate.
 33. The light emittingtransducer according to any of claims 14-32, further comprising a topencapsulating layer above the top electrode.
 34. The light emittingtransducer according to claim 32, wherein the bottom encapsulating layercomprises a nitride based layer or an oxide based layer or oxi-nitridebased layer.
 35. The light emitting transducer according to claim 33,wherein the top encapsulating layer comprises a nitride based layer oran oxide based layer or oxi-nitride based layer.
 36. The light emittingtransducer according to any of claims 14-35, wherein the top electrodecomprises a conductive polymer.
 37. The light emitting transduceraccording to claim 36, wherein the top electrode has a planar topelectrode surface.
 38. The light emitting transducer according to claim36 or 37, wherein the top electrode further comprises a metallicelectrode between the conductive polymer and the light emitting diodelayer.
 39. The light emitting transducer according to any of claims14-38, wherein all components of the light emitting transducer above thesubstrate form a thickness, which is 1/50 to 1/100 of a heightdifference between the repeating raised and depressed micro-scalesurface portions.
 40. The light emitting transducer according to any ofclaims 14-39, wherein the raised and depressed micro-scale surfaceportions have a height difference of 5-50 μm.
 41. The light emittingtransducer according to any of claims 14-40, further comprising aTFT-array having a plurality of interconnected thin-film transistors,the thin-film transistor corresponding with respective diodes at thelight emitting diode layer.
 42. The light emitting transducer accordingto claim 41, wherein the thin-film transistors comprise organicthin-film transistors.
 43. The light emitting transducer according toclaim 41, wherein the thin-film transistors comprise oxide thin-filmtransistors.
 44. The light emitting transducer according to any ofclaims 14-40, wherein the substrate is an optical element.
 45. The lightemitting transducer according to claim 44, wherein the bottom substratesurface is a lens.
 46. The light emitting transducer according to any ofclaims 14-40-, wherein the light emitting transducer is mounted on asilicone lens
 47. An optical element having a first surface, a secondsurface, and a silicone material between the first surface and thesecond surface, wherein the optical element further comprises thetransducer according to any of claims 14-40 attached to the firstsurface or the second surface.
 48. The light emitting transduceraccording to any of claims 14-47, further comprising a protection layerabove the top electrode, the protection layer comprising an elastic webor foil.
 49. The light emitting transducer according to any of claims15-??, wherein the light emitting diode layer is less stretchable andless compressible than is the substrate.